Allium 🧅

Allium is a genus of monocotyledonous flowering plants that includes hundreds of species, including the cultivated onion, garlic, scallion, shallot, leek, and chives. — Wikipedia

Allium is an implementation of onion routing written in Rust. It enables anonymous communication over encrypted tunnels. In addition to being used as a Rust library, Allium can also be run as a stand-alone daemon, which can be controlled over a TCP socket.

Features

• Asynchronous design based on the Tokio runtime
• Periodic, seamless tunnel reconstruction
• Fixed-size packets
• Cover traffic

Getting started

The documentation contains a short section on how to get started with the Allium library.

Daemon

The daemon can be installed with:

$ cargo install allium-daemon

After installation, the daemon can be run like this:

$ allium-daemon [config file path]

The Allium daemon requires a configuration file, which defaults to config.ini in the current working directory. A different path can be specified via an optional command line parameter. The configuration file must be in *.ini or *.toml format. Example ini-configuration:

[onion]
; The address and port on which the daemon listening for API connections
api_address = 127.0.0.1:4200
; The port on which connections from other peers in the onion network are accepted
p2p_port = 4201
; The address on which connections from other peers in the onion network are accepted
p2p_hostname = 127.0.0.1
; The path to a PEM-encoded RSA keypair used for signing messages
hostkey = testkey.pem
; The number of hops (excluding the destination) in each tunnel (should be at least 2)
hops = 2
; Enable or disable cover traffic
cover_traffic = true
; Duration of each round in seconds.
round_duration = 120 

[rps]
; The address and port the random-peer-sampling module is listening on
api_address = 127.0.0.1:4100

CLI Example

For testing purposes, a command-line interface is provided which can be run like this:

$ cargo run --example cli

Additionally, the logging level can be specified like this:

$ RUST_LOG=trace cargo run --example cli

Tests

Tests can be run with

cargo test

Known Issues

• During switchover, we kill the old tunnel without draining any possibly leftover Data messages. This may cause packet loss.
• Circuit IDs (and to some degree tunnel IDs) are generated randomly. Although unlikely, there might be duplicates.
• We don't sanitize the output from the RPS, so tunnels with loops or random cover tunnels with ourselves as destination might be possible, depending on the implementation of the RPS.

Future Work

• Write benchmarks and tune the performance
  • Reduce the number of allocations and copy operations
• Tunnels are generally torn down forcefully instead of being deconstructed iteratively, despite the necessary functionality being partially implemented